Evaluation of DNA markers for fish identification

Species substitution is a common commercial fraud, mainly applied to fish species. It is thus important to have analytical methods for species identification. DNA analysis can be a suitable technique: some mitochondrial genes are actually recognized as valuable markers for species discrimination. Aim of this work was thus to evaluate the capability of cytb and COI genes to discriminate the species of fish (n=89) which are commonly substituted. In the last four years of activity on field, the laboratory analysed, using the FINS method (Forensically Informative Nucleotide Sequencing), 146 samples, belonging to several fish species, sent by veterinary officers in the frame of their activities of control: in this work, results about number and kind of fraud are reported. Additionally, samples directly purchased by the lab were examined. The obtained results showed that the genetic markers have a high discriminatory power and that the method is highly suitable. The frequent detection of species substitution in the samples collected on field showed the importance of controlling this kind of frauds in the fish market.